Laking of blood by freezing and thawing

Abstract

The mechanism of laking by freezing and thawing 1 is not understood. Since it is known that drying through evaporation will cause laking, it is possible that drying through crystallization of water 2 may account for laking by freezing. But again since it is known that hypertonic solutions may cause laking, and since there is evidence that the freezing point of serum is somewhat higher than that of the intracellular liquids and therefore in freezing a concentration of the serum solids occurs, it may be that such laking is fundamentally the same as laking by hypertonic solutions.

It was observed that blood could be repeatedly frozen and thawed as in freezing point measurements with slight or no laking. But when blood was exposed a single time to a temperature considerably below the freezing point for some time, on thawing strong laking occurred. To gain information on the question as to what degree of cooling is necessary to cause laking and also as to the relation of time of exposure to such temperature to the degree of laking, the experiments, the results of which are herein reported, were performed. The blood of various animals including ox, dog, cat, and fowl has been used. Thus far no marked differences in the behavior of the different bloods have been observed. Summarized, the results show:

1. That slight or no laking occurs when the temperature of the blood is sufficiently lowered for the formation of crystals of ice if the blood is maintained at this temperature for but a short time.

2. When maintained at a temperature between a point slightly lower than that of the freezing point and minus one degree centigrade for ten minutes or more, laking occurs after the tube has remained at room temperature for some time.